若3^x=4,3^y=6,求9^2x-y+27^x - 知识问答

若3^x=4,3^y=6,求9^2x-y+27^x-y

2个回答

9^2x-y+27^x-y
=9^2x÷9^y-27^x÷27^y
=3^4x÷3^2y-3^3x÷3^3y
=(3^x)^4÷(3^y)^2-(3^x)^3÷(3^y)^3
=256÷36-64÷216
=184/27

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